Hi rpm surging problem - Johnson 115

[ArtSmart]

I am at the end of the rope on this one. So, any ideas would be appreciated. Recently bought a 2001 Johnson 115 (V4-60 loop). Ran it first time and it ran perfectly for 3 hours. Took it out next day and it would not run past 3000 rpm. It would kick in and then back out again and surge like that around 3000 rpm. It is not a fuel problem. By now I already replaced VRO pump rebuild carbs and ran it from a separate portable fuel tank with a short hose to the engine. Tested fuel pressure and it is good. Put new spark plugs - all to no avail. The only thing that was done to the engine between the first run and the next one, when the problem appeared is adjusting shifter linkage. Reading through some of the posts made me think, does this mottor have a shift interrupter switch? Can it be it?

 

[Walker]

Re: Hi rpm surging problem - Johnson 115

No shift interupt switch on that motor. Pull all your coils off and clean the ground straps and the block where they bolt on.

 

[ArtSmart]

Re: Hi rpm surging problem - Johnson 115

Checked coils seem to be fine. Coil grounds don't seem to have any corrosion on them. Is there any way to check coils (how often do they fail anyway?) and powerpack? How about the timing sensor?

 

[DJ]

Re: Hi rpm surging problem - Johnson 115

The connections can LOOK OK. Take them off and clean the connections.

 

[ArtSmart]

Re: Hi rpm surging problem - Johnson 115

I did clean the connections anyway. That didn't help. Besides I found one spark plug wire that did have a broun mark on it and looked like it was sparking to the engine block. replaced that with a new one but still no difference. I don't think it is a reed valves, because I ran the engine without air box and it doesn't seem to blow gas out of carburators. So the only suspects are colis, powerpack and timing sensor.

 

[ArtSmart]

Re: Hi rpm surging problem - Johnson 115

Ok, problem solved. After reading so many similar message with no endings I desided to take time and post my solution. May be it will make somebody's life easier.<br /><br />The engine had two problems intermitten lanyard switch and bad power pack. I checked the black/yellow wire on the powerpack connector with an Ohm meter and it was shorted to the ground. After playing with the lanyard switch for a while it became open circuit again. I'm not sure if the power pack was bad but I replaced it at the same time.

 

[Stumpys]

Re: Hi rpm surging problem - Johnson 115

ArtSmart.. I understand your grief. There are a lot of smart folks on here to help out, but good ole hands on training makes you learn a few things. Glad you found the problem.